Added EstimateIterationsResult to gather iteration estimate results

[dogeared]

POC:

EstimateIterationsResult estimateIterationsResult =
    KeyAlgorithms.estimateIterations(PBES2_HS256_A128KW, 100);

int index = 1;
for (Result r : estimateIterationsResult.getResults()) {
    System.out.println("Iteration: " + (index++) + ", workFactor=" + r.getWorkFactor() +
            ", duration=" + r.getDuration() + " ms");
}
System.out.println("estimated iterations: " + estimateIterationsResult.getEstimatedIterations());

Result:

Iteration: 1, workFactor=93745, duration=103 ms
Iteration: 2, workFactor=109460, duration=101 ms
Iteration: 3, workFactor=109560, duration=113 ms
Iteration: 4, workFactor=108738, duration=107 ms
Iteration: 5, workFactor=107922, duration=107 ms
Iteration: 6, workFactor=107112, duration=109 ms
Iteration: 7, workFactor=106308, duration=100 ms
Iteration: 8, workFactor=107482, duration=101 ms
Iteration: 9, workFactor=107582, duration=102 ms
Iteration: 10, workFactor=106775, duration=101 ms
Iteration: 11, workFactor=106875, duration=100 ms
Iteration: 12, workFactor=106975, duration=102 ms
Iteration: 13, workFactor=108338, duration=102 ms
Iteration: 14, workFactor=107525, duration=102 ms
Iteration: 15, workFactor=106718, duration=102 ms
Iteration: 16, workFactor=105917, duration=101 ms
Iteration: 17, workFactor=107087, duration=104 ms
Iteration: 18, workFactor=106283, duration=105 ms
Iteration: 19, workFactor=105485, duration=101 ms
Iteration: 20, workFactor=105585, duration=103 ms
Iteration: 21, workFactor=104793, duration=102 ms
Iteration: 22, workFactor=104007, duration=101 ms
Iteration: 23, workFactor=104107, duration=103 ms
Iteration: 24, workFactor=103326, duration=104 ms
Iteration: 25, workFactor=102551, duration=103 ms
Iteration: 26, workFactor=101781, duration=103 ms
Iteration: 27, workFactor=113172, duration=100 ms
Iteration: 28, workFactor=115583, duration=101 ms
Iteration: 29, workFactor=115683, duration=101 ms
Iteration: 30, workFactor=115783, duration=102 ms
estimated iterations: 113272